1. Field
This disclosure relates generally to electrical circuits, and more specifically, to a data processing system having a brown out detection circuit.
2. Related Art
Some data processing systems include a low power, or stand-by, mode where power is removed from most of the system during certain times to reduce power consumption. It is often desirable to maintain a power supply voltage to a small portion of the system, such as for example, a static random access memory (SRAM), to retain certain critical memory contents. However, an SRAM requires a specified minimum data retention voltage to prevent data loss. The power supply voltage provided to the SRAM during low power mode may become too low for reliable data retention. Also, a drop in the power supply voltage can occur anytime and can be due to a variety of reasons. When the supply voltage to the system SRAM falls below the minimum data retention voltage, it is important to inform the system of possible corrupted data.
A brown-out detector is used to monitor the power supply voltage and provide a warning when the monitored voltage falls below a predetermined voltage. The system can then take corrective action. Current brown out detectors are relatively inaccurate, so a relatively high voltage is required to guarantee correct system operation. As improving process technologies allow for the use of progressively lower power supply voltages, the accuracy of the brown-out detector becomes more important.
Therefore, what is needed is a brown-out detector that solves the above problems.